1. Field of the Invention
The present invention relates to a measurement device, and more particularly, to a measurement device and a measurement method for simultaneously measuring pressure and shear force.
2. Description of Related Art
Pressure is force per unit area applied in a direction perpendicular to a surface of an object. Shear force is force applied tangentially to the surface that causes sliding or torsional deformation. Since shear force is applied parallel to an action plane, it is also called tangential force.
Shear force may be measured by a magneto-resistive device and a capacitive device. A magneto-resistive device may measure variation of the shear force by a suspended magnet and magneto-resistive material. The magnet and the magneto-resistive material are placed in two layers respectively. A change of resistance can be used to calculate the change of the relative position, so as to infer the applied shear force. As for the capacitive device, the shear force can be measured by the variation of the internal capacitance value. An upper electrode and a lower electrode are included within the capacitive device. The upper electrode and the lower electrode are isolated by an insulator. The change in relative positions of the upper electrode and the lower electrode is calculated based on the capacitance values, and the applied shear force is thus inferred by the change in the relative positions.
During measuring the pressure and the shear force, the pressure and the shear force are measured separately. Currently, the pressure and the shear force on an object to be measured can not be detected simultaneously by a device or a method.
Moreover, since the conventional technique that measure pressure and shear force rely on electrical signals, consequently, the circuitry and transducer are coupled together. However, when any component of the device is damaged, the overall device will not be actuated and must be replaced as a whole, and thus the cost will be increased.
Therefore, there is a need for simultaneously measuring the pressure and the shear force on an object for the industrial application.